It is well known that light bars are commonly used in emergency vehicles, ambulances, highway patrol law enforcement vehicles and etc., mainly for the purpose of caution. The light bars have been widely used in China for about 20 years. The turning type light bars that have been used, although the appearance of which have many variations, mainly use tungsten light bulbs as the light source. The tungsten light bulb is a thermal light source with a low response frequency, only capable of working in the constant-on or low frequency blinking mode, and cannot work at a high frequency or generate a sense of urge. The power consumption of tungsten light bulbs is great, which increases the burden to the power supply system of the emergency vehicle. The tungsten light bulbs are not resistant to shocks, and have a short lifetime. Normally a tungsten light bulb has only a few hundred hours of lifetime. The rated lifetime of a halogen light bulb is only within 3000 hours. The electric-optical conversion efficiency for tungsten light bulbs is low, while the massive amount of heat generated thereby greatly effects the lifetime of the whole light bar. Hence, to solve the above problems, LEDs (light-emitting diodes) have been used as the light source, which have lower power consumption and longer lifetime.
The conventional light bars that are currently being used are a type of light bars that use LED as the light source. Such light bar usually includes a base, a plurality of LED light units disposed at the front and the back ends of the base, lenses that correspond to the LED light units, and supporting legs connected to the bottom of the base for connecting to the vehicle. The left and right ends of the base are connected to a light unit base respectively. An end cover and a plurality of LED lights are connected onto the light unit base.
However, the conventional light bar usually uses LEDs that have a diameter of 8 mm and a light emitting portion with a diameter of 5.8 mm. The corresponding lenses have a maximum diameter of 20 mm. The height of the light bar reaches 40 mm. The height of the light bar being too high will cause a waste of the materials for making the light bar.